Get the day signal
Power Window requests REE's peninsular real-time market price widget for the selected date. It prefers PVPC hourly prices when available and otherwise uses the spot market price series averaged to hourly values.
Methodology
We separate timing from consumption.
The app gives one grade for when you run the appliance and one label for the estimated electricity consumed by the selected load.
Estimate the chosen load
For every candidate window, the app multiplies each hour's price by the selected appliance load. The result is an energy-component estimate, not a full household bill with taxes, tolls, contracted power, or retailer-specific charges.
cost = sum((EUR per MWh / 1000) * appliance kW)
Normalize against the day
The cheapest average window gets a score near 100 and the most expensive window gets a score near 0. Midday hours receive a small bonus because they often align with stronger solar production, but price remains the main driver.
Show a simple A-F symbol
The A-F grade is a quick interpretation of the score for the selected day. It says whether the selected time window is efficient relative to the rest of that day.
- A 90-100: excellent timing
- B 78-89: very good timing
- C 64-77: decent timing
- D 50-63: below-average timing
- E 35-49: expensive timing
- F 0-34: avoid if flexible
Estimate appliance-style consumption
The colored A-G load label is inspired by appliance energy labels, but it is not an official EU certificate. It is based on estimated run energy:
estimated kWh = selected kW * selected hours
A short dishwasher run may show A or B, while a longer EV charge can show E, F, or G because the total electricity consumed is much larger.